Assembly for holding the interface of stationary outer structure of a nacelle and housing of a jet engine

ABSTRACT

The invention relates to an assembly for holding the interface of a stationary outer structure ( 15 ) of a nacelle ( 3 ) and housing ( 27 ) of a jet engine ( 5 ), said assembly including: a first raised element belonging to the upstream end of the stationary outer structure ( 15 ); a second raised element belonging to the downstream end of the housing ( 27 ), said first and second raised elements being formed so as to be placed in contact with each other; two half-rings ( 109 ) formed by a wall defining a recess that is formed so as to receive the first and second raised elements when the housing ( 27 ) and the stationary outer structure ( 15 ) are mounted edge to edge; and an abutment means formed so as to keep the first and second raised elements in the recess.

TECHNICAL FIELD

The present invention relates to an assembly for holding the interfaceof a jet nacelle and the structure of a nacelle reverser surroundingsaid jet engine.

The present invention also relates to a propulsion assembly comprisingsuch a holding assembly.

BRIEF DISCUSSION OF RELATED ART

An aircraft is generally moved by a propulsion assembly comprising a jetengine surrounded by a nacelle.

The jet engine comprises fan blades upstream that are actuated by amotor. The fan blades are surrounded by a case making it possible tomount said jet engine in the nacelle.

The fan of the jet engine is essentially made up of a rotary shaftbearing a plurality of vanes. At their radial end, the vanes arecircumferentially surrounded by a case.

The fan cases are generally machined metal elements.

The jet engine can be a dual-flow jet engine capable of generating a hotair flow (also called primary flow) coming from the combustion chamberof the jet engine, and a cold air flow (secondary flow) coming from thefan that circulates outside the jet engine through an annular channel,also called “stream,” formed between a fairing of the jet engine and aninner wall of the nacelle. Behind the nacelle, the two primary andsecondary flows mix.

This nacelle is generally equipped with a thrust reverser. During thelanding of an airplane, the thrust reverser makes it possible to improvethe braking capacity of the airplane by reorienting at least part of thethrust generated by the jet engine forward. During this phase, thereverser obstructs the gas jet nozzle and orients the jet flow from theengine toward the front of the nacelle, thereby generating acounter-thrust that is added to the braking of the airplane's wheels.

More specifically, a nacelle generally has a structure comprising an airintake upstream of the motor, a middle structure intended to surroundthe case of the jet engine, and a downstream structure comprising aninner fixed structure (IFS) and an outer fixed structure (OFS) intendedto surround the combustion chamber of the jet engine and housing thrustreverser means.

The thrust reverser means are varied and can be in the form of at leastone mobile cowl, called “thrust reversal cowls,” moving in translationowing to actuators in a direction substantially parallel to alongitudinal axis of the nacelle.

During this flight phase, the structure of the thrust reverser undergoesaxial aerodynamic forces that tend to cause the thrust reverser means towithdraw longitudinally relative to the jet engine.

So as not to pass all of these forces on to the fastening points of thedownstream structure on the mast, the upstream part of the downstreamstructure, in particular the fixed outer structure, is connected at thedownstream end of the fan casing of the jet engine.

The structure of the thrust reverser is generally made in two half-partsarticulated at the upper portion of the pylon, called “D-duct”structure. In this configuration, the holding between the casing and theouter fixed structure is done by a male part, generally supported by theouter fixed structure, cooperating in a female part, generally supportedby the casing.

However, such a configuration can only be suitable for a D-Ductstructure because the release of the two opposite structures can only bedone in a radial direction.

The downstream structure can also assume the form of an externalassembly in a single piece without a break in structural continuity,called “O-duct” structure. This outer assembly is dissociated from theinner structure surrounding the motor and is actuated to provide accessto the body of the motor through rectilinear movement toward the back ofthe nacelle beyond the withdrawal value necessary for the thrustreversal. The maintenance of the outer fixed structure and the casingcannot be done identically to the maintenance of the D-duct structures.

The holding is then done by bolts once the casing and the outer fixedstructure are mounted edge-to-edge.

However, such holding does not allow fast access to the motor.

BRIEF SUMMARY

One aim of the present invention is therefore to provide a holdingassembly allowing holding uniformly distributed over the circumferenceof the interface of the casing and the outer fixed structure, to reducemaintenance time, facilitate the latter and limit the number ofnecessary parts and the cost.

To that end, according to a first aspect, the invention relates to anassembly for holding the interface of a stationary outer structure of anacelle and housing of a jet engine, said assembly including:

-   -   a first raised element belonging to the upstream end of the        outer fixed structure;    -   a second raised element belonging to the downstream end of the        housing,    -   said first and second raised elements being formed so as to be        placed in contact with each other;    -   two half-rings formed by a wall defining a housing that is        formed so as to receive the first and second raised elements        when the casing and the outer fixed structure are mounted edge        to edge, and an abutment means formed so as to keep the first        and second raised elements in the housing.

The holding assembly according to the invention therefore makes itpossible to connect, via the half-rings, the downstream end of thecasing and the upstream end of the outer fixed structure of thedownstream structure housing the thrust reverser means.

The holding assembly according to the invention therefore makes itpossible to lock and unlock the interface of the casing and the outerfixed structure simply, effectively, and quickly while using a smallnumber of parts. The maintenance time as well as the cost are reducedand controlled.

Owing to the annular configuration of the invention, the holding isuniformly distributed on the circumference of the interface.

According to other features of the invention, the holding assembly ofthe invention comprises one or more of the following optional featuresconsidered alone or according to all possible combinations:

-   -   the wall forms a housing with a substantially U- or V-shaped        transverse section;    -   longitudinal and/or transverse play is present between the        non-facing surface of the raised elements and the wall forming        the housing;    -   at least one raised element has a ramp configured to cooperate        with at least one lateral edge of the wall that has an inclined        surface complementary to the ramp when said raised element is        inserted in the housing, which allows a slight misalignment of        the two raised elements before closing the half-ring;    -   at least one raised element comprises a sealing means so as to        ensure sealing between the first raised element and the second        raised element when the latter are received in the housing,        which makes it possible to avoid any leak of the cold air flow        and the hot air flow so as not to create disruptions in the        performance of the propulsion assembly according to the        invention;    -   the raised element(s) comprise a transverse centering means        relative to the casing and the outer fixed structure without        making the holding assembly of the invention heavier;    -   at least one half-ring comprises a lever means making it        possible to facilitate the transition from the locking position,        in which the two raised elements are received in the housing, to        the unlocking position in which the raised elements are outside        the housing;    -   the lever means is a protuberance configured to be attached to        the end of a half-ring and bear on at least one fixed surface;    -   the two half-rings are secured to one another by fastening        means, which makes it possible to ensure the tightening and        holding force of the raised elements;    -   the fastening means comprise at least one bolt or at least one        three-point bolt with a hook;    -   at least one half-ring comprises a foolproof device so as to        avoid locking said half-ring without the raised elements;    -   at least one half-ring is formed from a multitude of parts so as        to adapt the flexibility or rigidity of the half-ring;    -   the part comprising the housing is made in several sectors        secured to one another by fastening means, which advantageously        makes it possible to lift the half-ring on the parts with a        small travel;    -   at least one sector is mounted hingedly on the next one;    -   the articulation of the sector is associated with one or two        levers mounted on either side of said sector so as to facilitate        the unlocking of the sector;    -   at least one half-ring comprises a holding means configured to        support said half-ring in the unlocking position;    -   the holding means is in the form of a connecting rod fastened on        said half-ring and on a holder fastened on the casing or on the        outer fixed structure;    -   each half-ring is hingedly mounted substantially at 12:00 on the        outer fixed structure.

According to another aspect, the invention relates to a propulsionassembly comprising a jet engine housed in a nacelle that can beconnected to the aircraft by an attachment pylon, the jet enginecomprising fan blades surrounded by a casing mounted edge to edge withan outer fixed structure of the downstream structure of the nacelle thathouses thrust reverser means, said propulsion assembly comprising aholding assembly according to the invention.

According to other features of the invention, the inventive propulsionassembly comprises one or more of the following optional features,considered alone or according to all technically possible combinations:

-   -   at least one half-ring is mounted substantially at 12:00 on the        nacelle, which makes it possible to have the greatest possible        clearance and facilitate access to the jet engine;    -   at least one half-ring is hinged on the attachment mast or on        the casing via a stationary pivot;    -   a connecting rod connecting the pivot points positioned on each        side of the attachment mast ensures the fastening of the two        half-rings to one another so as to ensure peripheral charge        continuity;    -   at least one half-ring is mounted on the upstream cowl at the        outer fixed structure;    -   the two half-rings are supported by the upstream cowl with play,        which helps with proper operation and prevents interfacing        problems due to the hyperstatic effects between the outer fixed        structure and the casing;    -   at least one half-ring is connected to the cowl via a partition        or a fitting configured to receive a half-ring.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood upon reading the followingnon-limiting description, done in reference to the appended figures.

FIG. 1 is a longitudinal cross-section of a propulsion assemblyaccording to the invention;

FIG. 2 is a perspective view of said propulsion assembly of FIG. 1;

FIG. 3 is a perspective view of one embodiment of a holding assemblyaccording to the invention;

FIGS. 4 to 7 are transverse cross-sections of alternative embodiments ofFIG. 3;

FIG. 8 is a perspective view of one embodiment of the attachment of thetwo half-rings of the assembly according to the invention;

FIGS. 9 to 14 are side views of alternative embodiments of FIG. 8;

FIGS. 15 and 16 are side views of embodiments for fastening the twohalf-rings of the holding assembly according to the invention to oneanother;

FIG. 17 is a transverse cross-section of an embodiment of the holdingassembly according to the invention;

FIGS. 18 to 21 are perspective side views of a half-ring of the holdingassembly according to the invention;

FIGS. 22 and 23 are perspective side views of an alternative of theholding assembly according to the invention;

FIG. 24 is a front perspective view of an alternative of the holdingassembly of the invention mounted on a propulsion assembly;

FIG. 25 is an enlargement of zone XXV of FIG. 24;

FIGS. 26 to 28 are transverse cross-sections of a half-ring of theholding assembly according to the invention mounted on the cowl of theouter fixed structure of the propulsion assembly of the invention;

FIG. 29 is an enlargement of zone XXIX of the embodiment of FIG. 28;

FIGS. 30 to 31 are perspective views of alternatives for attaching ahalf-ring of the holding assembly according to the invention.

DETAILED DESCRIPTION

According to the embodiment shown in FIG. 1, the propulsion assembly 1according to the invention comprises a nacelle 3 surrounding a jetengine 5 that both have an axis of revolution or primary longitudinalaxis 6. The nacelle 3 typically comprises an upstream air intakestructure 7, a middle structure 9 surrounding the blades of a fan 11 ofthe jet engine 5, and a downstream structure 13. The downstreamstructure 13 comprises, in a known manner, an outer structure 15 (OFS),housing thrust reverser means 17, and an inner structure 19 (IFS). Thethrust reverser means here are in the form of a mobile cowl 21 inlongitudinal translation toward the downstream direction of the nacelle3 and a fixed grid 23 through which the cold air flow is deflected. Thenacelle 3 is secured downstream using any suitable means, in particularconnecting rods, to a suspension mast, not shown in FIG. 1, intended toattach the nacelle 3 under an aircraft wing.

The outer fixed structure 15 and the inner fixed structure 19 alsodefine an annular flow channel 25 through which the cold air flow isintended to circulate.

The inner fixed structure 19 is intended to cover a downstream portionof the jet engine extending downstream of the blades of the fan 11.

The fan blades 11 of the jet engine are topped circumferentially by acasing 27. The casing 27 is intended to be attached to the outer fixedstructure 15 of the downstream structure. More particularly, theupstream end of the casing 27 is configured to be connected to thedownstream end of the outer fixed structure 15. In that case, the casing27 and the outer fixed structure are said to be “mounted edge to edge.”

According to the invention, a holding assembly 101 makes it possible tohold and lock the outer structure 15 and the casing 27. The assemblyaccording to the invention 101 comprises:

-   -   a first raised element 105 belonging to the upstream end of the        outer fixed structure 15;    -   a second raised element 107 belonging to the downstream end of        the casing 27;    -   said first 105 and second 107 raised elements being configured        to be put in contact with one another;    -   two half-rings 109 formed by a wall defining a housing 111,        configured to receive the first 105 and second 107 raised        elements when the casing 27 and the outer fixed structure 15 are        mounted edge to edge, and abutment means 113 configured to keep        the first 105 and second 107 elements in the housing 111.

The holding assembly of the invention 101 makes it possible to connect,via the two half-rings 109, the interface of the downstream end of thecasing 27 and the upstream end of the outer fixed structure 15.

Due to the annular configuration of the invention, the holding isuniformly distributed over the circumference of the interface.

The holding assembly according to the invention 101 also makes itpossible to lock and unlock this interface simply, effectively, quickly,and using a small number of parts. The maintenance time, costs and massare reduced and controlled relative to the prior art. In fact, to lockor unlock the holding assembly, one need only translate the casing 27and the outer fixed structure 15 longitudinally relative to thelongitudinal axis, then pivot each half-ring 109 on the raised elements105 and 107 placed opposite one another or respectively release saidhalf-ring 109 by pivoting outside the raised elements 105 and 107. As aresult, it is pointless to separate a male part and a female part or toremove periodic means to release the casing 27 and the outer fixedstructure 15. The abutment means 113 advantageously make it possible tokeep the two raised elements 105 and 107 in the housing 111.

The “locking position” is defined as the position of the inventiveholding assembly 101 in which the two raised elements 105 and 107belonging to the casing 27 and the outer fixed structure 15 are receivedin the housing 111 of at least one half-ring 109.

The “unlocking” or “maintenance” position is the position of theinventive assembly 101 in which the two raised elements 105 and 107belonging to the casing 27 and the outer fixed structure 15 are outsidethe housing 111 of at least one half-ring 109.

The wall of each half-ring 109 therefore defines the housing 111 and theabutment means 113. The abutment means 113 is for example formed in thelateral extension of the wall defining the housing 111. At least one, oreven both of the half-rings 109 can be a double knife, i.e. the wallforms a housing 111 with a transverse section in the shape of a bowl, inparticular with a substantially V- or U-shaped transverse section. Inthat case, the raised elements 105 and 107 are in the form of a clipnormal or transverse to the longitudinal axis 6 of the nacelle 3.Advantageously, the raised elements 105 and 107 can have a continuousstructure so as to guarantee a uniform load distribution over saidraised elements 105 and 107.

As shown in FIGS. 4 and 5, when the first 105 and second 107 elementsare received in the housing 111, said elements 105 and 107 are incontact. According to one alternative, the wall forming the housing 111and the abutment means 113 of the half-ring 109 is not in contact withthe opposite surface, i.e. not across from, said elements 105 and 107,which defines play 115 and 117. The play 115 and/or 117 makes itpossible to limit the transverse and/or longitudinal travel of theraised elements 105 and 107. The play 115 can therefore be longitudinal,i.e. along the primary longitudinal axis 6 of the nacelle, or transverse117, i.e. along an axis perpendicular to the primary axis 6. It ispossible to have play that is both longitudinal 115 and transverse 117as shown in FIGS. 4 and 5. The play 115 and 117 advantageously makes itpossible to take the manufacturing limit and shape tolerance of theraised elements 105 and 107 to be held into account. Advantageously,such play 115 and 117 allows placement of the interface of the casing 27and the outer fixed structure 15 without stressing the half-ring 109. Asa result, in the case of longitudinal play 115, when the jet engine 5 isoperating, the outer fixed structure 15 undergoes thrust that tends tomove it away from the casing 27. The two raised elements 105 and 107then come into contact with the abutment means 113 and are therebyretained in the housing 111.

At least one raised element 105 or 107 can have a ramp 121 configured tocooperate with at least one lateral edge of the wall that has aninclined surface 123 complementary to the ramp 121 when said raisedelement 105 or 107 is inserted into the housing 111, which allows aslight misalignment of the two raised elements 105 and 107 beforeclosing the half-ring 109. In this way, it is advantageously possible tobring the two raised elements 105 and 107 closer together during lockingof the casing 27 and the outer fixed structure 15. According to theembodiment shown in FIGS. 4 and 5, the walls of the two elements 105 and107 not across from each one another have such a ramp 121. In that case,the lateral edges of the wall 113 each have an inclined surface 123 onwhich a ramp 121 can slide. As shown in FIG. 4, during the introductionof the raised elements 105 and 107 into the housing 111, the ramp 121slides on the inclined surface 123 until the raised elements 105 and 107are introduced into the housing 111.

Typically, the ramp 121 can have an angle smaller than or equal to about30°.

As shown in FIG. 6, at least one raised element 105 can comprise asealing means 131 so as to ensure sealing between the first raisedelement 105 and the second raised element 107 when the latter are housedin the housing 111, which makes it possible to avoid any leak of thecold air flow and hot air flow so as not to generate disruptions on theperformance of the propulsion assembly 1 according to the invention. Thesealing means 131 can assume the form of a seal housed in the housing133 formed in one of the raised elements 105.

The raised element(s) 105 and 107 can comprise a transverse centeringmeans relative to the longitudinal axis 6 of the nacelle 3, which makesit possible to facilitate closing of the casing 27 and the outer fixedstructure 15 without making the inventive holding assembly 101 heavier.Such a centering means makes it possible to limit the forces created bythe explosion of a fan blade 11, which tends to misalign and separatethe casing 27 and the outer fixed structure 15.

The centering means can assume the form of a protuberance 151 belongingto the casing 27 configured to enter a recess 153 formed in the outerfixed structure 15 (see FIG. 7). Thus, any rotational force caused bythe rotation of the imbalanced fan can be absorbed. As a result, eachhalf-ring 109 only bears the axial forces.

At least one or even both of the half-rings 109 can comprise a levermeans 161 making it possible to facilitate the locking and unlocking ofsaid half-ring 109 on the raised elements 105 and 107 (see FIGS. 8 to14). The lever means makes it possible to reduce the angular travel ofsaid half-ring 109. In particular, in the case where a half-ring 109 ishinged using a pivot at 12:00 of the nacelle, i.e. near or on theattachment mast 31 when the latter is seen from the inlet of the nacelle3, it is sometimes impossible to open a half-ring 109 enough to releasethe casing 27 and the outer fixed structure 15. As a result, the leversystem 161 makes it possible to ensure the release of the casing 27 andsaid outer fixed structure 15 with a small pivot angle, i.e. less than15°. Thus, the lever system 161 can be mounted upstream of the pivotpoint of the half-rings 109.

The lever means can be a protuberance 161 configured to be attached tothe half-ring 109, in particular at an end, and to bear on at least oneinner surface 165 of the holder 163 of each half-ring 109.Advantageously, in the locking position, the lever means 161 is not incontact with the casing 27, the outer fixed structure 15 or the holder163 of said ring 109 so as not to generate parasitic forces.

As shown in FIGS. 9 and 10, from the locking position, one moves thehalf-ring 109 by a small angle, smaller than 15°, so as to release saidelements 105 and 107. As a result, the protuberance 161 comes intocontact with the surface 165 of the holder, which results in producing alever effect thereby requiring the half-ring 109 to completely releasesaid raised elements 105 and 107. In the case of FIGS. 9 and 10, theholder 165 on which the lever means 161 bears is positioned on the“lower” surface, i.e. the surface closest to the interface of the casing27 and the outer fixed structure 15.

According to an alternative shown in FIGS. 11 and 12, the holder 167 onwhich the lever means 161 bears is positioned on the “upper” surface,i.e. the surface furthest from the interface of the casing 27 and theouter fixed structure 15. This configuration allows assistance for thefitting of the half-ring 109 on the raised elements 105 and 107.

According to still another embodiment shown in FIGS. 13 and 14, thelever means can comprise two protuberances 161 a and 161 b connected toone another and each configured to bear on the lower surface and theupper surface.

As shown in FIG. 15, the two half-rings 109 can be fastened to oneanother by a fastening means, which makes it possible to ensure thetightening and holding force for the raised elements 105 and 107. Aradial centering element can be added either by adding a centering pinor by integrating complementary shapes in both ends of the half-rings.

In the locking position, the two half-rings 109 can advantageously beattached at the 6:00 position relative to the nacelle 3 in front view.In that case, the fastening means of said half-rings 109 are located inthat 6:00 position. To ensure the tightening and holding force of theraised elements 105 and 107, the locking of the two half-rings 109 canbe done under tension, in particular by mechanical and manual fasteningmeans.

Thus, the fastening means can comprise at least one bolt 171 (see FIG.15), which makes it possible to lock the two half-rings 109 simply andinexpensively. To that end, the free end of a half-ring 109 can comprisetwo walls 173 substantially perpendicular to the rest of the half-rings,in other words going in the radial direction transverse to thelongitudinal axis 3 of the nacelle 3. Said two walls are then facingeach other when the two half-rings 109 are in the locking position. Thebolt 171 can be associated with a nut passing through the two walls 173so as to maintain the locking. The interface of the two walls 173 can beproduced with play 175 after tightening the bolt 171, which is done soas to guarantee the holding force of the two rings 109 relative to oneanother. In that configuration, other bearing (not shown) can existproduced between the inner surface of the half-rings 109 and thesurfaces not facing the raised elements 105 and 107.

According to the embodiment of FIG. 16, the fastening means comprise athree-point bolt with a hook 181, which makes it possible to have apermanent bolt on the half-ring 109. According to the configurationshown in said FIG. 16, one of the half-rings 109 supports the part ofthe bolt comprising the hook 183 and the other half-ring 109 supportsthe part comprising the retaining member 185 of said hook 187.Advantageously, the retaining member 185 can be adjustable so as to makeit possible to adjust the locking tension created by the cooperation ofthe hook 187 and the retaining member 185 when the two half-rings 109are in the locking position.

According to one alternative, the contact of the half-rings 109 in thelocking position is done in a plane substantially close to the alignmentof the three-point bolt 181. The abutment of the half-rings can beidentical to that of the preceding configuration.

According to another alternative not shown, at least two three-pointbolts with hooks 181 are mounted on either side of the half-rings 109,which makes it possible to increase the locking reliability.

According to another alternative embodiment, a three-point bolt 181 canhave some of its components lined so as to improve the reliability ofsaid bolt 181. In particular, it is possible to have a single retainingmember 185 configured to receive two distinct hooks 187 mounted acrossfrom the half-rings 109. It is also possible to line the connectionleading the axis of the three-point bolt 181 to the fastener on the hook187 so as to guarantee a high reliability level. Likewise, the pivot ofthe hook 187 can be lined by the presence of two concentric pivots withthe same axis placed one in the other. Furthermore, the fastening meanscan be supported by a single-piece surrounding structure tolerating thedamages that may also be borne by the half-ring 109.

In that configuration, as one example that is not shown, a first lateralband can overlap on one side of the housing receiving a first raisedelement 105 and a second lateral band overlapping the other raisedelement 107. The lateral bands can come together substantially in the12:00 position of the nacelle 3.

At least one half-ring 109 can comprise a foolproof device 191 so as toavoid closing and locking said half-ring 109 without the raised elements105 and 107, i.e. without the two raised elements 105 and 107 beingreceived in the housing 111. The foolproof device 191 can assume theform of a longitudinal extension 191 of one of the walls of the abutmentmeans 113 (see FIG. 17). As a result, this extension 191 abuts againstthe raised element 105 of the outer fixed structure or the casing.According to one alternative, the foolproof device 191 can assume theform of two longitudinal extensions of the walls of the abutment means113. Furthermore, such a foolproof device is seen by the operator, whothen identifies that one of the raised elements 105 and 107 has not beenreceived in the housing 111 of the half-ring 109.

The foolproof device 191 can be local, multiple or continuous. In otherwords, the foolproof device 191 can extend over all or part of theperiphery of the half-ring 109 in one or more sectors.

At least one or even both of the half-rings 109 can be made in a singlepiece or formed from a multitude of parts so as to adapt the flexibilityor rigidity of the half-ring 109. In the event a half-ring 109 is madein several parts, it is possible to add a substantially annularreinforcing means, in particular on the outer wall of said half-ring109.

In this way, a half-ring 109 can be made up of two parts. The first partcan comprise the hinge and the lock and the second part can comprise thehousing 111 configured to receive the first 105 and second 107 raisedelements. The second part can be made in a single piece or with severalsectors, and/or from several materials, such as aluminum or titanium. Inthe case where the second part is made in several sectors, the sectorscan be connected to one another for example by rivets. The presence ofseveral sectors advantageously makes it possible to lift the half-ring109 on the parts with a small travel, in particular less than 10°.

Thus, at least one or even each sector 201 a, 201 b can be mountedhingedly on the following one, as shown in FIGS. 18 to 21.

As shown in FIG. 18, a sector 201 a is connected to an adjacent sector201 b by a pin 203 allowing the pivoting of the sector 201 a.

The positioning configuration of the pivot is done according to FIGS. 18and 19 depending on the position of the pulling force so as to returnthe hinge point to the appropriate plane.

As shown in FIG. 19, the sector 201 a can contain an abutment at thehinge 205 to help with the opening of the following sector.

As shown in FIGS. 20 and 21, the hinge of the sector 201 a is associatedwith one or two levers 211 mounted on either side of said sector 201 aso as to facilitate the unlocking and lifting of the sector 201 a. Thelever(s) 211 can bear on the casing 27 and/or on the outer fixedstructure 15. As illustrated in FIG. 21, the rotation of the firstsector 201 a drives the contact of the lever 211 on the fixed surface ofthe casing 27 or the outer fixed structure 15. Owing to this contact,the second sector 201 b can also lift to reach the unlocking position.

At least one or even both of the half-rings 109 can comprise a holdingmeans configured to support said half-ring 109 in the unlockingposition. As shown in FIGS. 22 and 23, the holding means can assume theform of a connecting rod 221 fastened on said half-ring 109 and on aholder 223 a and 223 b secured on the casing 27 or on the outer fixedstructure 15, in particular on one of the raised elements 105 or 107. Tothat end, the half-ring 109 can comprise openings 225 and 227 so as notto interfere with the holders fastened on one of the raised elements 105and 107 when the half-ring 109 is in the locking position, i.e. housingthe two raised elements 105 and 107. More precisely, the holder 223 aand 223 b can be made up of a first fitting 223 a and a second fitting223 b, the first fitting being configured to receive the pivoting end ofthe connecting rod 221 and the second fitting 223 b being able toreceive the end of the connecting rod 221 connected to the half-ring109. Typically, the first fitting 223 a and the second fitting 223 b arepositioned on the same side of the half-ring 109.

According to another alternative shown in FIGS. 24 and 25, the holdingmeans can comprise a fitting 231 mounted in the cowl 233 of the outerfixed structure, which makes it possible not to perform the release atthe half-ring 109 and to reduce the mass of said holding means. To thatend, the cowl 233 can be formed from two parts configured to be liftedin the unlocking position and which are fastened in the normal operatingposition at the 6:00 position of the nacelle 3. The fitting 231 is thenarranged downstream of the cowl 233 and comprises a housing 235.Arranged on the half-ring 109 is a holder 237 comprising a rod 239configured to cooperate with the housing 235. Thus, simply, when theoperator wishes to separate the cowl 233 and the half-ring 109, saidoperator removes the rod 239 from the housing 235.

The inventive assembly 101 can comprise a means for detecting theposition of the components of the assembly relative to one another, i.e.raised elements 105 and 107, half-rings 109. As an example, it ispossible to use a detection means in the form of permanent electronicsensors, such as a proximity sensor. Furthermore, it is possible toposition said sensors, for example at the 6:00 part of the twohalf-rings 109 or at the fastening means of the two half-rings 109.

Furthermore, the inventive assembly 101 can comprise a means fordetecting the locking tension of the two half-rings 109.

According to an embodiment not shown in FIGS. 26 to 28, at least onehalf-ring 109 is connected to the cover of the fan 251, rigidly or not,which is hinged substantially at the 12:00 part of the nacelle 3. Thus,advantageously, it is possible to use said cover of the fan 251 as asupport for at least one or even both half-rings 109. To that end, saidhalf-ring 109 can be associated with the structure of the cover of thefan 251 rigidly, for example via a partition 253 (see FIG. 26) or via afitting 255 in which the half-ring 109 can be received (see FIGS. 27 and28).

In the embodiment shown in FIGS. 27 and 28, said half-ring 109 ismounted in the fitting 255 so as to have lateral play 257, which allowsbetter gripping of the cowl 251 during the release of the half-ring 109.

As shown in FIG. 29, at least one or even both of the half-rings 109 aremounted on the upper part of the outer fixed structure 15 and thereforethe nacelle 3, which makes it possible to have the greatest possiblerelease and facilitate access to the jet engine 5. Thus, one or evenboth of the half-rings 109 can be hingedly mounted substantially at12:00 of the outer fixed structure 15 and therefore of the nacelle 3.More precisely, each half-ring 109 can be hinged on the attachment mast31 via a stationary pivot 261. To that end, a fitting (not shown) can beattached on the attachment mast 31. It is also possible to unite the twofittings of the two half-rings 109 by a rigid inner structure 263 asclose as possible to the traction axis so as to avoid any force createdby the lever arm-type movement created by the unlocking of a half-ring109.

The traction axis is defined here by an axis passing through a surfaceparallel to the surface to be gripped through which the circumferentiallocking forces pass.

According to an alternative not shown, the half-ring(s) 109 can befastened via a fitting on the casing 27, which makes it possible tocontain the alignment of the two half-rings 109 relative to theinterface of the casing 27 and the outer fixed structure 15. It ispossible to unite the two fittings using a rigid structure inside theattachment mast 31 as close as possible to the traction axis so as onthe one hand to avoid any lever arm-type force created by the unlockingof the half-ring 109 and on the other hand to ensure the peripheral loadintegrity.

According to one alternative, the stationary fittings of the precedingembodiments can be replaced by a connecting rod connecting the pivotpoints arranged on each side of the attachment mast 31 so as to ensurethe peripheral load continuity. Typically, said connecting rod can beplaced in a plane close to the traction axis.

In this case, the connecting rod is “floating,” i.e. mounted through theattachment mast 31 so as not to create additional force between the twohalf-rings 109 and react any differential movement between thestationary structure of the nacelle 3 and that of the jet engine 5.

According to an embodiment shown in FIG. 30, the floating connecting rod301 can pass through a housing 302 formed in the holder 303 of thehalf-ring 109 that is supported by the casing 27. Thus, advantageously,when the half-ring 109 is in the locking position, i.e. retaining thecasing 27 and the outer fixed structure 15, the connecting rod 301 isnot in contact with the walls of the housing 302. One end 309 of theconnecting rod 171 can be configured so as to cooperate with thecomplementary part of the half-ring 109. To that end, the end oppositethe connecting rod 301 has two protuberances 311 and 313 configured togrip the free end 309 of the connecting rod 301. The two ends 309 and311, 313 are fastened to one another for example via a rod or a bolt(not shown). Advantageously, the holder 303 only undergoes the forces tokeep the half-ring in position. According to an alternative shown inFIG. 31, the ends 311 and 313 can assume the form of hooks configured togrip a rod 321 of the end 309 of the connecting rod 301.

1. An assembly for holding an interface of a stationary outer structureof a nacelle and a casing of a jet engine, including: a first raisedelement belonging to an upstream end of the outer fixed structure; asecond raised element belonging to a downstream end of the housing; saidfirst and second raised elements being formed so as to be placed incontact with each other; two half-rings formed by a wall defining ahousing that is formed so as to receive the first and second raisedelements when the casing and the outer fixed structure are mounted edgeto edge, and an abutment means formed so as to keep the first and secondraised elements in the housing.
 2. The holding assembly according toclaim 1, wherein the wall forms a housing with a substantially U- orV-shaped transverse section.
 3. The holding assembly according to claim1, wherein longitudinal and/or transverse play is present between thenon-facing surface of the raised elements and the wall forming thehousing.
 4. The holding assembly according to claim 1, wherein at leastone raised element has a ramp configured to cooperate with at least onelateral edge of the wall that has an inclined surface complementary tothe ramp when said raised element is inserted in the housing.
 5. Theholding assembly according to claim 1, wherein at least one raisedelement comprises a sealing means so as to ensure sealing between thefirst raised element and the second raised element when the latter arereceived in the housing.
 6. The holding assembly according to claim 1,wherein the raised element(s) comprise a transverse centering meansrelative to a longitudinal axis of the nacelle.
 7. The holding assemblyaccording to claim 1, wherein at least one half-ring comprises a levermeans making it possible to facilitate a transition from a lockingposition, in which the two raised elements are received in the housing,to an unlocking position in which the raised elements are outside thehousing.
 8. The holding assembly according to claim 7, wherein the levermeans is a protuberance configured to be attached to the end of ahalf-ring and bear on at least one fixed surface.
 9. The holdingassembly according to claim 1, wherein the two half-rings are secured toone another by fastening means.
 10. The holding assembly according toclaim 9, wherein the fastening means comprise at least one bolt or atleast one three-point bolt with a hook.
 11. The holding assemblyaccording to claim 1, wherein at least one half-ring comprises afoolproof device.
 12. The holding assembly according to claim 1, whereinat least one half-ring is formed from a multitude of parts.
 13. Theholding assembly according to claim 12, wherein the part comprising thehousing is made in several sectors secured to one another by fasteningmeans.
 14. The holding assembly according to claim 13, wherein at leastone sector is mounted hingedly on the next one.
 15. The holding assemblyaccording to claim 14, wherein the articulation of the sector isassociated with one or two levers mounted on either side of said sectorso as to facilitate the unlocking of the sector.
 16. The holdingassembly according to claim 1, wherein at least one half-ring comprisesa holding means configured to support said half-ring in the unlockingposition.
 17. The holding assembly according to claim 16, wherein theholding means is in the form of a connecting rod fastened on saidhalf-ring and on a holder fastened on the casing or on the outer fixedstructure.
 18. The holding assembly according to claim 1, wherein eachhalf-ring is hingedly mounted substantially at 12:00 on the outer fixedstructure.
 19. A propulsion assembly comprising a jet engine housed in anacelle that can be connected to an aircraft by an attachment pylon, thejet engine comprising fan blades surrounded by a casing mounted edge toedge with an outer fixed structure of the downstream structure of thenacelle that houses thrust reverser means, said propulsion assemblycomprising a holding assembly according to claim
 1. 20. The propulsionassembly according to claim 19, wherein at least one half-ring ismounted substantially at 12:00 on the nacelle.
 21. The propulsionassembly according to claim 19, wherein at least one half-ring is hingedon the attachment mast or on the casing via a stationary pivot.
 22. Thepropulsion assembly according to claim 19, wherein a connecting rodconnecting the pivot points positioned on each side of the attachmentmast ensures the fastening of the half-rings to one another.
 23. Thepropulsion assembly according to claim 19, wherein at least onehalf-ring is mounted on the upstream cowl at the outer fixed structure.24. The propulsion assembly according to claim 23, wherein the twohalf-rings are supported by the upstream cowl with play.
 25. Thepropulsion assembly according to claim 19, wherein at least onehalf-ring is connected to the cowl via a partition of a fittingconfigured to receive a half-ring.